


Common Ground

by Fortune_Maiden



Category: AI: The Somnium Files (Video Game)
Genre: Fluff, Gen, Holidays, Humor, Set roughly four years prior to the main story
Language: English
Status: Completed
Published: 2019-12-25
Updated: 2019-12-25
Packaged: 2021-02-26 03:48:05
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,819
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21843190
Author URL: https://archiveofourown.org/users/Fortune_Maiden/pseuds/Fortune_Maiden
Summary: Inspired by a Somnium, Date decides to spend New Year's Eve with Mizuki.Aiba helps out.
Relationships: Aiba & Date Kaname, Date Kaname & Okiura Mizuki
Comments: 7
Kudos: 68
Collections: Yuletide 2019





	Common Ground

**Author's Note:**

  * For [NightsMistress](https://archiveofourown.org/users/NightsMistress/gifts).



> I hope you enjoy! <3

12/30/20XX

Kaoru Hide was innocent of murder. Six minutes in the man’s Somnium was enough for Kaname Date to draw that conclusion. Of course, it didn’t really matter what he thought, Aiba would sternly point out. It would fall to the rest of the ABIS Team to review and dissect the footage. Their analysis would be reliable, she’d quip unnecessarily as Date would take one last look at the groggy man in the opposite Psync machine chair and walk out.

He would report in to Pewter and the Boss, answer their routine questions about his findings and general mental state (questions Aiba always answered), and then, with the Boss’ dismissal, get into his car, drive home for the night, and put the case out of his mind, same as he always did.

A high ranked member of the yakuza had been murdered the day before Christmas. It gave the police department something to grumble about as they hustled about for a quick suspect, hoping to end the year off on a clear note. From what Date gathered, the dead man had been involved in some art forgery ring, and as the police investigated, a single man’s name came up in nearly all of the witness testimonies. That man was Kaoru Hide, some bum salesman that looked like he didn’t know a thing about art (not that Date could judge), let alone crime families. Still, the police dutifully tracked him down, and when his questioning revealed nothing, ABIS was called in.

In six minutes, Date had to turn a stuffed rabbit inside out, dump a bag of cash into a toilet, and make a key out of a paperclip to open the door to the heavens. Date didn’t really see how any of those things pointed to the mind of a killer (aside from maybe the money in the toilet thing), but he rarely understood the dreams of the people he investigated. It didn’t help that the most information he got about the people he was diving into was a single page summary of the case, but the Boss and Aiba both assured him he didn’t need to know more. A year ago, Date might have resisted that assurance. But a year ago, he didn’t have Aiba to at least help him parse the things he saw in the dreams.

Not that he would tell her that. Besides, it didn’t matter anymore. Six minutes was all the time Date spent on any case. The end of his dive marked the end of his involvement, and Date no longer had any reason to think about any of the things he saw in that Somnium.

And yet, one scene kept replaying in his head.

Literally.

“Will you stop that?” Date snapped, hands tightening around the wheel as he tried to focus his right eye on the not-empty-enough nighttime road.

Out of his left eye, he saw a door opening and two shadowy figures stand in front of a small flimsily decorated Christmas tree. The taller figure stood stoically in front of it. The smaller figure, that of a child’s, jumped up with raised arms. It was a quick scene, over in a flash, but as quickly as it would fade away, the door would open for it again.

“You’re still thinking about it,” Aiba’s voice echoed in his head smugly.

“That doesn’t mean you have to keep replaying it. I’m driving.”

The scene faded but Aiba still didn’t focus her gaze onto the road. Date would have to reluctantly accept that as a compromise. He’d had Aiba for a little over a year now, so he’d gotten somewhat used to having to drive with only one eye on the road, while the other did as it pleased. What he wasn’t used to though, and frankly never would be, was her ever present…well, _presence_ , in his head.

“It’s unlike you to dwell on a dive,” Aiba said.

“I’m not dwelling on it,” he replied. “You’re the one that keeps replaying it.”

“Because you’re dwelling on it,” Aiba said again, more firmly this time. To be extra insistent, she replayed the segment, yet again. “Is there something about this scene that you noticed?”

“Nothing related to the case.”

“Then, something related to you, personally?”

Date didn’t like her tone. Despite being an AI, Aiba sounded too human. Their link gave her access to his thoughts, but he was still able to keep her out of some things. And whenever he did, she would grow inquisitive. He sighed.

“Look, it’s a kid, an old dude, and a Christmas tree. Not exactly something you expect to find in the mind of a suspected yakuza killer.”

“True,” Aiba agreed. “According to the case files, the child in the dream is likely the daughter of one of the persons of interest. They’d met our subject a couple of days after the killing.”

“And what, had a Christmas party?” Date remarked. “Actually, don’t tell me. I’m not actually interested.”

“They did not have a Christmas party,” Aiba answered anyway. “They merely happened to be at the same location at the same time. No prior acquaintanceship either. I do not know how the tree or the daughter fits in. I imagine the detectives on the case can answer that question.”

“Yeah, yeah, remind me to hit up Kaniza later,” Date remarked noncommittally. He hadn’t been coy when he said he wasn’t interested. This wasn’t his case. He was just called in last minute (as always) because he was the only Psyncer not to have made other end-of-year plans. That scene with the Christmas tree just seemed interesting was all.

“How old’s the daughter anyway?” Date found himself asking.

“Eight years old. Why?”

“No reason.”

“That’s not an—oh!” Aiba audibly perked up. “I see now.”

“No, you don’t.” Date cringed as she started up the scene again. “Stop that.”

“This is what you were really thinking of, wasn’t it?” Aiba asked lightly. The latest replay of the scene had a slight variation. The shadow figures were replaced to two familiar backs. The tall figure had turned into Date. The child was Mizuki. As before, the child jumped up with her arms in the air. Only now they were Mizuki’s arms, and her long hair swung as she jumped. When her head turned to the figure that was now Date, there was a wondrous smile on her face.

The real Mizuki did not smile like that.

“Were you really thinking about decorating a tree with Mizuki?” Aiba asked. “I’m shocked.”

“Don’t be, because I wasn’t,” Date snapped. “Just thinking how we don’t really decorate for Christmas.”

“You’re not the decorating type. You’re the type who needs an average of twenty-three reminders a week to remember to vacuum your place.”

“I do not,” Date retorted. Then with a frown, added, “Average of twenty-three? Seriously?”

“Very serious. I’m an AI. I can remember every single reminder I’ve given you. Oh, on a positive note though, since Mizuki moved in, the average number of reminders you need to pick up your tissues—

“Okay, okay, I get it. Enough. _Please_ ,” Date grimaced. If he wasn’t in the middle of driving home, he might have smacked his head against a wall. “I’ll try to do better.”

“I highly doubt anything will come of this, but duly noted.” It was her _burning enthusiasm_ that made Date decide to make a real effort to take better care of his apartment going forward. He could make it his New Year’s resolution or something. He still needed one of those.

As for the tree though… Date really hadn’t been thinking about decorating one with Mizuki, but now that Aiba put the thought in his head, he found it stuck. Maybe that really was why that one scene in the Somnium stood out so much. That moment had been important enough to Hide to be in his dream. There was something warm about it. When he’d seen it in the Somnium, he thought for a moment he could feel what Hide had felt then. Happiness. Satisfaction. The knowledge that he’d brightened a little girl’s day.

Mizuki was that girl’s age. Did she get excited about decorating Christmas trees too?

“You’re still thinking about it,” Aiba’s voice echoed in his mind.

“Alright fine, I am,” Date agreed, before she could replay the scene yet again. “Something wrong with that?”

“No,” Aiba’s voice was low. “Perhaps the last Psync had some sort of influence…”

“It didn’t,” Date assured her. She and the Boss and Pewter were always on his case about that. And yet none of them ever offered any sort of explanation on what that actually _meant._ “Look, it’s been a long night, and this was kinda the most exciting thing that’s happened on it. We’ll get home, go to bed, and tomorrow I won’t be thinking about this at all.”

* * *

Date was still thinking about the tree the next morning.

In fact, his thoughts about it had gotten stronger. He found himself wandering around his apartment mentally noting where a tree could fit. Aiba had been tasked with taking measurements of the space, snide commentary accompanying the task. Mizuki had left for the day (Date didn’t know where), so she was not around to offer her own commentary on the matter.

“It’s the season for it. Stop being such a Grinch,” Date remarked.

“ _Was_ the season for it, Date. Past tense,” Aiba informed him. “Christmas was 6 days ago. Today is New Year’s Eve. If you’re suddenly in such a festive mood, you should be focusing on that.”

“I am. Just with a… Christmas-y twist to it. There’s nothing wrong with wanting to decorate a tree. Speaking of, do you think we should go with a real one or a fake?”

“And where are we supposed to find a tree, exactly?” Aiba asked.

“That’s your job, not mine,” Date told her. “Do a search around the city. Get me the cheapest tree and decoration prices you can find.”

“Uh-huh,” Aiba still did not sound convinced. “Isn’t it a little late for the sudden Christmas spirit? Do I need to remind you how you spent the actual holiday last week?”

She didn’t, but did so anyway. Date had spent the night at Golden Yokocho getting drunk and cursing out the couples of the world. Mama had decked out the bar a bit (no tree though) and ordered some fried chicken, but she was right there in joining Date’s laments about being single on Christmas. They had a good time, Date thought.

“Where was Renju anyway?” Date suddenly asked. “He wasn’t there.”

“Mama said he was out on a date,” Aiba answered. “At which point you burst into tears and went on an angry tirade about so-called normies and sappy holiday romances. Would you like a playback?”

“No!” Date sighed. When did his life become like this? “What about Shoko? Where was she anyway?”

“Working, probably.”

“You don’t know?”

“I don’t live in _her_ eye socket.”

“Fair enough,” Date agreed. “And Mizuki?”

Aiba didn’t answer right away. In fact, the pause replacing her typical quick responses could have been taken as a stunned silence.

“You don’t know?” Date pressed.

“Do you?” Aiba asked in turn, though the answer was obvious.

“Nope.” She’d been fast asleep when Date finally got home that night, but where she spent the day, and whether or not she did anything for the holiday was a mystery to him.

“Date…” Aiba’s voice was soft. “You are a terrible guardian.”

To this, Date could only nod in agreement. He’d thought he was doing Mizuki a favor taking her in. He truly believed it was better for her to stay with him rather than Renju or Shoko. There had been an adjustment period, but she didn’t cry as much anymore, so he thought that was a sign of improvement. She didn’t particularly _like_ Date or talk to him, but that was just the type of girl she was, and Date thought it was better to let her have her space. He wasn’t out to be her replacement guardian. He just wanted her to have a quiet place to stay until her parents got their shit together.

But leaving an eight-year-old alone on Christmas seemed too cruel.

“So, mind doing that search around the city now?” Date asked after a moment’s contemplation.

“On it!”

* * *

Date hadn’t expected it to be so difficult to find a tree. Most places had taken down their Christmas decorations in favor of emphasizing the New Year merchandise. The few places that did still sell trees, didn’t have particularly nice ones left. Date and Aiba couldn’t agree on the type of tree.

“If you get a fake one, we can reuse it next year,” Aiba argued, gaze focused intently on the boxes of fake trees. Date’s own gaze was on their price tags.

“They’re too expensive.”

“The reusability will make up for the cost in time.”

“Mizuki may not even be living with me next year.”

“You don’t know that. And you can still put up a tree for yourself.”

“That’s lame.”

Though he supposed if he met a girl, and brought her home, it might have been worth a few points to show off his holiday spirit.

“That’s never going to happen,” Aiba said critically.

“Quit reading my thoughts.”

“Then quit thinking them.”

“Look,” Date snapped, then noting the stares he was getting, covered his ear to make it look as though he was talking into a headset. “We are doing this for Mizuki. Don’t you think she’d like a real tree?”

“Real trees are a responsibility. Someone who can’t even bother to do the dishes can’t be trusted with a tree.”

“For the love of—we got home late last night. Mizuki was sleeping. Did _you_ want to wake her?”

“Mizuki was not sleeping this morning. The dishes are still unwashed.”

Date paused. He tried not to form the thought that in all his excitement about buying a tree, he’d completely forgotten about them (and that Aiba didn’t remind him), but her smug chuckle told him he was unsuccessful. He sighed.

“Look…” he said. “I don’t know much about kids.”

“You don’t know much about anything, Date.”

“I don’t know much about _kids_ ,” Date repeated pointedly. “But we should go with a real tree. That’s just this feeling I have.”

“Based on what?”

“I don’t know.” It was an honest an answer as Date could give. He didn’t know where this sudden stubbornness came from. He liked to call it his detective’s intuition, but sometimes he just felt he knew some things and didn’t have any basis for them. Perhaps it was related to his memories from further back.

Though how would a Christmas tree of all things fit in them?

“Was the tree in the Somnium real?” Aiba asked quietly.

“I don’t think so.”

“Okay,” Aiba herself grew weirdly quiet in times like this. Perhaps she’d sensed the unease Date was starting to feel. “So Mizuki would be happier with a real tree, right? Fine, but _I_ get to pick it out!”

To Aiba’s credit, she did pick out a nice tree. She’d dragged Date halfway across the city to find it (and it ended up not even being that much cheaper than the fake one she’d wanted initially), but it was a decently pretty tree. It was on the smaller side, but it has a deep green color, and a fresh smell. When they finally put it up in the corner of the apartment, it fit right in.

But it wasn’t enough to just get the tree, of course. The whole point was to decorate it. And for that, Aiba dragged Date to six more stores, all in the name of getting the best decorations at the best prices. Date made a mental note to make her present these best prices ahead of time in the future. The more zeroes appeared on the register, the more skeptical he became. Not that he was particularly resistant to the selection Aiba put together (though she did veto the sexy Santa girl figurines he wanted and threatened to explode if he bought them anyway).

It wasn’t until all their purchases had invaded the couch and the table, that it occurred to Date that they may have gone a little overboard.

“It’s fine, right? This way Mizuki will have a selection,” Aiba said.

“Yeah, I agree.”

Per Aiba’s instructions, he began to organize the decorations. The tree was small enough that Mizuki would only really need help putting on the star, so he would leave things to her.

Everything was set!

* * *

“Date, what is this?”

Having lived with Mizuki for the better part of the year, Date had long grown used to her too-venomous voice. He had dared to imagine a more enthused reaction from her, but a sour glare was really more her style.

“Mizuki, you’re back,” he said, jumping up from the small space he’d made for himself on the couch. “Finally.” It had taken him and Aiba far less time than expected to organize things. Date even had time to vacuum and do the dishes in the interim.

“Why is there a tree in here?” Mizuki demanded. “And what’s with all this stuff? Did you rob a crafts store?”

“No.” Date ignored the suspicious sounding scoff from Aiba. “I bought this. With money.”

“Duh.”

“I was thinking, we didn’t really do anything for the holidays this year,” he said brightly (remembering the speech he’d rehearsed). “So, why not decorate a Christmas tree together? What do you say?”

“It’s not Christmas, stupid. It’s New Year’s,” Mizuki said flatly. She crossed her arms. “Who’s ever heard of a New Year’s Tree?”

“We could start the tradition ourselves…or something,” Date offered.

_Actually, there are several cultures where a New Year’s tree—_

_Aiba, not now please_ , Date shot back at her. He tried to give Mizuki his best smile. This was going downhill fast.

“Or I can just decorate it myself for now, and then if you change your mind later… the night’s still young right? Oh hey, do you want dinner?”

“No,” Mizuki’s frown deepened. “And I don’t have time to watch you fool around. I have plans.”

“Wait, what plans?”

“New Year’s plans.”

“Oh, are you going to Ren—

“Daddy’s working. I’m going to a friend’s house. She’s downstairs now. I just came to get some things.” Mizuki’s replies were terse. She pushed past Date and the mountain of decorations to grab a bag under Date’s bed. As she stuffed her things into in, Date quickly glanced out the window. There was indeed a car parked in front of their house with its lights on.

“So, who’s this friend of yours?” Date asked, eager to make some conversation.

“You don’t know her.”

“Are you staying over?”

“Donno.”

“Mizuki, come on, you have to tell me these things,” Date said with a heavy sigh. “If Renju calls asking about you—

“He won’t,” Mizuki said in the same flat icy tone as always. The swift way she zipped up her bag betrayed her irritation though, so Date decided to drop the topic.

“Alright, cool. Just, uh, call me or something if you do decide to stay over. Or if you want to be picked up. I’m not working tonight so I’ll be here, watching TV, I guess.”

“Kay.” Mizuki shrugged noncommittally and went to the door, not looking up at Date at any point.

“Er, Happy New Year’s,” Date called to her before she could slam the door behind her.

The force of her swing slowed down.

“Yeah. Thanks,” she muttered quietly. She closed the door after that, and Date listened to the sound of her footsteps fading down the hallway. He moved towards the window and watched her small figure get into the car, and then the car drive off. He watched until it was out of view before finally sinking to his knees.

“Date…” Aiba’s voice was soft for once.

“I feel like an idiot right now,” Date sighed. He felt a sudden twitch in his eye socket, and then his fake eye popped out, and took on a small bear-like form. “She has a phone. I could have just called and _asked_ if she wanted to decorate a tree together.”

“She would have said no,” Aiba admitted. “But if it helps, I got carried away too. Your enthusiasm was infectious.”

“My bad.”

“No, I didn’t mind it. It was surprisingly nice,” Aiba said. “But I did not expect Mizuki to react to the idea so poorly.”

“Me either.”

“Why did she refuse like that?” From anyone else it would have sounded mocking, but Aiba sounded genuinely confused. Date stared at her. With how she usually talked, it was sometimes easy to forget she was an AI and not an actual human.

“Hey, you heard her. Kid’s got plans,” Date answered sarcastically, then shook his head. “Mizuki has a lot going on right now . The wound to my pride stings—a lot—but honestly, I think it’s great that she has a friend to spend New Year’s with.”

“I see,” Aiba accepted the answer solemnly. “New Year’s is complicated.”

“I’ll say. ’Course, this doesn’t change the fact that we spent a crap ton of cash on this stuff,” Date picked himself up. “Now what?”

“What do you mean?”

“It’s New Year’s and we have the night ahead of us. And honestly, I bought the damn tree. I still want to decorate it.”

“Oh! I see,” Aiba’s voice perked up.

“’Course, if you don’t want to, there’s always the fallback plan of getting drunk at Golden Yo—

“Absolutely not!” Aiba snapped. “Even if the likelihood of it happening is less than 0.1%, you told Mizuki you would pick her up if she asked. You _cannot_ touch a drop of alcohol tonight.”

“Dammit, is that what I agreed to?”

“Yes.” Aiba was insistent, but happily so. “I guess it can’t be helped then. I’ll help you decorate.” She jumped on his outstretched palm and let herself be carried up to his shoulder. She scanned the pile of spheres and tinsel. “I have to say, this will be my first time decorating a Christmas tree.”

“Yeah?” Date said, with a good-natured chuckle. “Actually, as far as I remember, this is going to be a first for me too. Guess this is a common ground for us.”

“Is that right?” Aiba asked. “Then, I’ll run a scan to let us determine the optimal decoration pattern. If I leave it you—

“Keep talking like that, and I won’t let you put the star on the top.”

“…Fine.”

* * *

Mizuki ended up coming home that night after all.

When Date woke up the next morning to greet the new year, he couldn’t help but notice there were more decorations on the tree than what he and Aiba put up.

**Author's Note:**

> Thank you for reading! 
> 
> I hope you liked this story! It honestly started out as 'Date is influenced by something he sees in a Somnium'...and then it turned silly.
> 
> (Full disclosure: the case in the beginning was inspired by a somewhat obscure VN called Hotel Dusk.)


End file.
